Stock-market hawks saw this one from a mile away.

Allergan shares jumped over 5 percent last week, after the U.S. Food and Drug Administration approved its anti-wrinkle housewife staple Botox for use on chronic migraine headaches.

Ironic, seeing as the Irvine drug company just lost $600 million in an October lawsuit that accused them of marketing their product for unapproved uses — such as, well, treating migraines. But that settlement is chump change next to the extra $1 billion per year they're expecting to make on the new, improved Botox franchise.

Equally ironic:

The Italian National Research Council's Institute of Neuroscience warned consumers in 2008 that Botox could be dangerous if it spread from the face to the brain. The same year, 16 deaths by Botox were reported to the FDA, due to unexpected spread of the drug to other parts of the body. Then there's the fact that possible side effects of Botox include — get this — chronic headaches.

Currently, Botox is Allergan's No. 1 cash cow, bringing in over a quarter of its total revenue.

Side-note for animal lovers (if lab mice can be considered animals): Discovery of the new treatment could have something to do with the massive spike in Botox animal testing from 2003 to 2008. According to Humane Society International, the tests kill tens of thousands of mice per year.

Let us know: Would you consider tossing your Migranal prescription for some Botox to the dome?

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